|“||Would you like to be ejected? Like, not from the room, but out of an airlock?||”|
— Lady Casilda, to Freezo
Lady Casilda is the captain of the passenger ship The Saturnine, and the planeswalker of Carcosa. She is the second most significant NPC planeswalker in Season 4 (with the first being Hyperion Max, of course) and occasional antagonist throughout the series.
The Carcosa Shard which allows Lady Casilda's ship to travel between planes requires the sacrifice of living individuals to operate; Casilda herself has therefore become cruel and detached in spite of her graceful demeanor. She is capable of sacrificing innocents, brainwashing her own crew, and using undead servants as weapons. She also has strong sexual desires, having had sex with both Bobby Pancakes and Bobson Dugnutt (the latter of whom she named her "chief consort").
Her ship, the Saturnine, is decorated in a distinctive Steampunk style and she enforces three ranks of crewmen on the ship: the Favored who are her personal servants, the Bellows Men who operate the Shard, and the Gillmen who are the low-ranked menial servants. The Friends were forced to intervene on the Saturnine to prevent Bonathon Kndd being sacrificed to the Carcosa Shard; they prevented this, resulting in the destruction of the Saturnine as the Shard failed, while Lady Casilda apparently escaped any punishment due to her position on the Planeswalker council.
Lady Casilda takes her revenge on the Friends by later coming aboard their ship, the Heart of Glass, while the Friends are in Freezo's tower. She has the crew brainwashed, the craft redecorated, and begins forming a hierarchy of Favored; she also intercepts the zombie of Bobby Pancakes who was created by Titania, to use as a weapon against the Friends. In a confrontation on the bridge of the Heart of Glass over the phylactery that controls Bobby, Casilda is thrown to the floor and Philge brutally stomps on her neck, killing her instantly.
Lady Casilda appears to be based on the character Cassilda from the play The King In Yellow which is the most common fictional reference for Carcosa. The poem describing Carcosa which is used in multiple Cthulhu Mythos games and references is introduced as Cassilda's Song:
|“|| Songs that the Hyades shall sing,
Where flap the tatters of the King,
Must die unheard in
— Cassilda's Song, The King In Yellow